The use of gaseous fuels, such as hydrogen or compressed natural gas, for vehicles is generally known. Such fuels can represent an alternative to petroleum as a fuel source for motor vehicles, but are generally required to be stored at an elevated or high pressure in a storage tank. Typical storage tanks and their associated mounting systems for compressed gaseous fuels include various components that can raise the cost and complexity of manufacturing an alternative fuel vehicle. In addition, such storage tank systems often result in a loss of interior cabin volume or trunk volume in an automotive vehicle. Thus, there remains a need in the relevant art for a modular fuel storage system that overcomes the aforementioned and other disadvantages.